Now that the evenings are quickly drawing in, the April installed street lighting at Llanbedr has come into its own. These illumined a previously largely unlit stretch of the A494. Like the experimental cats' eyes that till their replacement formerly graced the crown of the Clwyd Gate, the Llanebdr street lights are LEDs. They omit an unusually crisp & intense white light with, to my eyes at any rate, a wavelength that produces a slightly greenish or blue-ish hue.
It's great to see white lights back in vogue. If my school physics serves me well, white light came from mercury vapour or argon vapour that replaced incandescent lamps. White lights were progressively replaced from the 1960s with the now familiar orange of the sodium lamps. Sodium lighting is more economical than mercury vapour and components last longer, although I think they are more expensive to replace.
Those in Rhuthun/Ruthin town centre ro me look to be high pressure sodium lamps whose discharge is a whiter pinky-orange than the familiar burnt orangey-brown of low pressure sodium lights. The town's lights therefore appear more natural and they make the night environment more pleasant but there is greater degree of light pollution.
The LEDs, on the other hand, are better still. There's much less pollution and the clarity (when new, as now) is such that you could easily drive on the A494 without headlights (not recommended, though).
It's great to see white lights back in vogue. If my school physics serves me well, white light came from mercury vapour or argon vapour that replaced incandescent lamps. White lights were progressively replaced from the 1960s with the now familiar orange of the sodium lamps. Sodium lighting is more economical than mercury vapour and components last longer, although I think they are more expensive to replace.
Those in Rhuthun/Ruthin town centre ro me look to be high pressure sodium lamps whose discharge is a whiter pinky-orange than the familiar burnt orangey-brown of low pressure sodium lights. The town's lights therefore appear more natural and they make the night environment more pleasant but there is greater degree of light pollution.
The LEDs, on the other hand, are better still. There's much less pollution and the clarity (when new, as now) is such that you could easily drive on the A494 without headlights (not recommended, though).